Grease extractor for kitchen ventilating systems

ABSTRACT

An extractor for grease and other condensable contaminants in the exhaust stream of a kitchen ventilating system features a wide depressed entrance chamber and inlet slot adjacent to a wide baffle where centrifugal swirling of the exhaust stream is initiated. Above the entrance chamber is a horizontally elongated mixing chamber containing a plurality of swirl-inducing baffles or fins which amplify and accelerate the centrifugal swirling of the grease-laden exhaust stream. A rising exhaust or discharge chamber containing an automatic fire damper leads from the downstream end of the mixing chamber for connection with a chimney duct containing an exhaust fan for the high velocity discharge of the cleansed exhaust stream. The extractor has a self-contained electrically controlled flushing and firesuppressing system.

v United States Patent 1 91 1111 3,802,329 -Wright Apr. 9, 1974 [5 GREASE EXTRACTOR FOR KITCHEN VENTILATING SYSTEMS Primary Examiner-Meyer Perlin Assistant Examiner-Ronald C. Capossel [76] Inventor: Lyle E. Wright, PO. Box 127,

Lanham, Md 20801 Attorney, Agent, or Firm B. P. F1shburne, Jr. [22] Filed: Aug. 18, 1972 [57] ABSTRACT 2 App]. N 231,981 An extractor for grease and other condensable contaminants in the exhaust stream of a kitchen ventilating system features a wide depressed entrance cham- [52] Cl 98/115 SSIDIG' 55/238 bet and inlet slot adjacent to a wide baffle where cen- 126,099 A trifugal swirling of the exhaust stream is initiated. Above the entrance chamber i a horizontally elon [58] new of Search 98/115 gated mixing chamber containing a plurality of swirl- 55/235 3 3 3 2 2 inducing baffles or fins which amplify and accelerate 6/2 9 9 0 the centrifugal swirling of the grease-laden exhaust stream. A rising exhaust or discharge chamber con- [56] References cued taining an automatic fire damper leads from the down- UNITED STATES PATENTS stream end of the mixing chamber for connection with 3,616,744 II/ 1971 Jensen 98/115 K a chimney duct containing an exhaust fan for the high 2,618,133 11/1952 Kennedy 55/446 X velocity discharge of the cleansed exhaust stream. The 3 1 1967 Weaver at 93/115 K extractor has a self-contained electrically controlled 2,400,179 5/1946 Venable 55/446 x fl hi and fi i g System 3,117,353 l/l964 Edwards 248/224 X 3,564,989 2/1971 Williams 98/115 K 4 Claims, 6 Drawing Figures PATENTEMPR 9 1914 SHE] 2 [IF 3 GREASE EXTRACTOR FOR KITCHEN VENTILATING SYSTEMS BACKGROUND OF THE INVENTION The prior art contains a number of teachings relating to the extraction of grease and other combustible contaminants from kitchenexhaustgas streams. Some examples of the patented prior art are U.S. Pat. Nos. 2,813,477; 3,055,285; 3,207,058 and 3,247,776 to A. K. Gaylord, and U. S. Pat. No. 3,490,206 to De Witt H. Doane.

The principal objective of this invention is to improve upon the known prior art relating to grease extractors for kitchen ventilating systems in terms of efficiency of operation and economy of manufacturing and installation of the extractor apparatus. Additionally, the invention possesses some totally new advantages and structural features and an improved mode of operation not taught or suggested by the prior art. More particularly, the invention features an extractor body or housing including plural interacting chamber portions and exhaust stream influencing baffles which are configured in such a way as to impart to the extractor a greatly increased ability to remove grease and other contaminants including hydrocarbons from the exhaust stream as compared to the prior art. The improved configuration of the extractor also greatly increases its firesuppressing and fire-extinguishing ability as compared to the prior art, and the arrangement for periodically flushing away accumulated grease from the internal surfaces of the apparatus has been improved.

Another feature of the invention resides in a simplified, economical and very secure mounting for the entire unitary body portion of the apparatus on a vertical wall or the like. The arrangement is such that the apparatus may be removed conveniently at any time.

Other features and advantages of the invention will become apparent during the course of the following description.

BRIEF DESCRIPTION OF DRAWING FIGURES I DETAILED DESCRIPTION Referring to the drawings'in detail, wherein like numerals designate like parts throughout the same, the numeral 10 designates in its entirety an extractor unit for grease and other contaminants found inthe exhaust air stream being drawn from a'kitchen above a cooking range or the like by suitable suction means. This air stream is frequently laden with grease and cooking oil vapors as well as other contaminants including hydrocarbons and the purpose of the unit 10 is to remove from the exhaust air stream as completely as possible all of the contaminants so that clean air, relatively free of pollutants, will be discharged into the atmosphere outside of the kitchen.

The numeral 1 1 designates a vertical wall adjacent to which a cooking range or grill, not shown, is positioned and immediately above which the extractor unit 10 is mounted during operation. The unit 10 comprises a lower horizontally elongated entrance chamber 12, for the grease laden air stream, which chamber is generally rectangular in cross section, FIG. 1, and somewhat elongated vertically in cross section. As shown in FIGS. 3 and 5, the inlet chamber 12 is sufficiently long horizontally to span a wide cooking apparatus or range, immediately above the latter and along the supporting wall 11. As best shown in FIGS. 1 and 4, the entire extractor unit 10 is conveniently and securely detachably mounted on the vertical wall 11 by pairs of horizontally elongated interlocking hanger plates 13 and 14, the former being dependingly secured to the rear vertical wall of the inlet chamber 12 and the latter being upstandingly fixedly secured to the wall 11. The hanger plates 13 which lie close to the back wall of the chamber 12 are received downwardly in the narrow spaces between the plates 14 and the wall 11. This mounting arrangement is very secure and stable since the interlocking plates 13 and 14 may, in a typical installation, extend for two feet or more horizontally along the back of the inlet chamber 12 which might be three feet long horizontally. Additionally, the compact mounting means allows the unit 10 to lie flush against the wall 11 with very little spacing and allows the entire unit 10 to be lifted from the wall and to be easily replaced thereon without additional fasteners such as screws or the like.

At the top of the inlet chamber 12 and at the transverse center thereof, FIG. 3, a mixing chamber 15 of considerably lesser width than the chamber 12 extends forwardly from the inlet chamber and wall, as shown. The mixing chamber 15 is rectangular in cross section, FIG. 5, and is slightly elongated vertically but more nearly square in cross section than the depressed inlet chamber 12, In a typical installation, the mixing chamber 15 may project forwardly from the wall 11 by about 22 inches. It is to be understood that the dimensions mentioned herein are illustrative only to show the relative proportions of the different compartments or chambers and are not critical. These dimensions will vary considerably from installation-to-installation depending upon the kind and size of cooking equipment to be serviced. Nevertheless, the configuration of the extractor unit 10 in all installations will remain basically as illustrated and the difference will be in size rather than in shape or configuration as the latter is very important to the improved mode of operation embodied in the invention.

At the forward or outlet end of the mixing chamber 15 there is provided a rising exhaust or outlet chamber 16 or passageway, adapted to be connected with a conventional exhaust duct 17 containing a suitable exhaust fan, not shown. Thus, it may be seen that the extractor unit 10 embodies three basic chambers 12, 15 and 16 in a unitized body or apparatus 10. The mixing and exhaust chambers 15 and 16 are of the same width transversely, FIG. 3, while the depressed inlet chamber 12 is quite long in a horizontal direction and rather deep vertically as compared to its width away from the wall 11 which is relatively narrow, FIG. 1.

The inlet chamber 12 is equipped near its top and on its forward side away from the wall 11 with an air stream inlet slot 18 where the grease laden air from the cooking apparatus is initially drawn into the extractor unit, as indicated by the arrows 19. The inlet slot 18, as shown in FIG. 5, preferably extends for the entire horizontal width of the chamber 12 so that all of the contaminated air rising from the range or grill will be quickly drawn into the extractor with minimum resistance. immediately inwardly of the inlet slot 18 is a downwardly inclined baffle plate 20 preferably set at an angle of about 45 to the vertical walls of the chamber 12. The baffle plate 20 also extends for the full horizontal width of the chamber 12 and slot 18. Its lower edge is spaced somewhat above the lower edge of the slot 18 as shown in FIG. 1. The contaminated air stream drawn into the chamber 12 through the slot 18 is deflected sharply downwardly by the baffle plate 20 as indicated by the arrow 21. This causes the air stream to pass near the bottom of the depressed inlet chamber 12 and to have initially imparted to it a rather strong turbulence and the beginning of a centrifugal swirling action within the inlet chamber 12, before the turbulent stream is drawn upwardly toward the entrance of the mixing chamber 15.

It will be understood that the action of the suction fan, not shown, in the exhaust duct 17 constantly pulls the grease laden air from the grill or range through the slot 18 and in to the apparatus. After swirling in the depressed chamber 12, the air stream flows vertically upwardly in the chamber 12 and enters the bottom of mixing chamber in a region close to the wall 11 and on the rearward or right hand side of a first vertical bafl'le plate 22 which rises from the bottom of the mixing chamber at the open top of the mixing chamber 12. The baffle plate 22 has a rearwardly rolled transversely curved top extension 23 which imparts to the rising air stream a clockwise centrifugal swirling movement near the vertical center of the mixing chamber 15. This action furthers and increases the centrifugal swirling already initiated in the lower chamber 12. The baffle plate 22 terminates near the vertical center of the mixing chamber 15.

Somewhat forwardly in the chamber 15 near the longitudinal center thereof is a second vertical baffle plate 24 which depends fixedly from the top wall of the chamber 15 and terminates near the vertical center of the chamber 15 in a forwardly and upwardly curled transversely curved extension 25 similar to the extension 23 but reversed therefrom. Both baffle plates 22 and 24 extend for the entire width of chamber 15, see FIG. 5, and the several baffle plates in the chamber 15 are equidistantly spaced apart as shown. A third baffle plate 26 rises from the bottom wall of mixing chamber 15 and terminates near the vertical center of the mixing chamber in a curved extension 27 identical to the extension 23. At their bottoms, the two upstanding baffle plates 22 and 26 have plural laterally spaced drain passages 28 for the return of liquid grease and flushing water and detergent into the top of chamber 12 and ultimately into bottom wall outlet-drains 29 of the chamber 12 located near the opposite ends thereof.

Another depending vertical baffle plate 30 which is also the interior wall of exhaust chamber 16 forms the forward end of mixing chamber 12 and terminates at the vertical center of the mixing chamber in a curved extension 31 identical to the extension 25. It may now be seen that the terminal extensions 23, 25, 27 and 31 of the several vertical baffle plates alternate in direction, are equidistantly spaced, and are tangent to a common horizontal plane at approximately the vertical center of the mixing chamber 15. With this arrangement, the grease laden air stream from the cooking appliance follows generally the zigzag path through the mixing chamber 15 indicated by the arrows 32 after leaving the top of the entrance chamber 12 and passing around the curved extension 23 of the first vertical baffle plate 22. Above the first bafile plate 22 in the top portion of chamber 15 the flowing air stream has its direction abruptly reversed from upward to downward as the swirling action continues. A second reversal takes place at the bottom of chamber 15 between the two baffles 22 and 26 and the curved extensions 27 and 25 act on the upwardly flowing stream to again induce and strengthen the clockwise swirling and centrifugal action as indicated by the arrows 33.

Another reversal of flow takes place above the baffle plate 26 and a final reversal occurs in the bottom of chamber 15 below the baffle plate 30 and forwardly of the baffle plate 26, from which region the stream flows vertically upwardly into and through the exhaust passage 16 and ultimately into the duct 17 leading to atmosphere. In the region of each centrifugal swirl inducing extension 23, 25, 27 and 31 and in the region of each flow reversal in the system designated by the arrows 32, large amounts of entrained grease and oil droplets and other contaminants are deposited on the walls of the several vertical baffle plates and also on the side walls of the mixing chamber 15. Since the flow of laden air from the entrance chamber 12 which is wide is into a constricted or narrower mixing chamber 15, FIG. 3, there is naturally an increase in velocity of the exhaust air stream due to a well known physical principle that the velocity of a flowing fluid is increased in constrictions while its pressure is decreased. This increase in velocity of the stream, while turbulence, change of direction, and centrifugal swirling, continues causes increasing amounts of contaminants to be deposited on the walls and baffle plates, so that the ultimate stream entering the. vertical exhaust passage 16 is relatively clean or free of pollutants. Laboratory tests of the invention have shown conclusively that, in comparison to known prior art extractors, greater percentages of grease and hydrocarbons, as well as other contaminants, are removed from the exhaust stream. This not only improves conditions in the kitchen but considerably reduces atmospheric pollution external to the kitchen and the extractor unit.

To shield the unit 10 from heat directly above the cooking apparatus, a heavy layer 34 of heat insulation.

is applied to the bottom wall of the chambers 15 and 16 in any conventional manner. Additional to the effect of the insulation 34 in the chamber 15, there is a gradual expansion of the gaseous stream flowing through the chamber 15 due to the above-mentioned physical principle of fluids flowing through a constriction. This reduction in pressure and resulting expansion causes cooling of the stream and increased condensation of contaminants on the walls and baffles of the mixing chamber. This also reduces the fire hazard in the system.

In the exhaust or outlet chamber 16, which is vertical and which has the same width as the mixing chamber 15, FIG. 3, there is provided a fire damper 35 which is held open normally by a fusible link 36 and biased to a closed position by suitable torsion spring means 37 interconnecting the shaft 38 of the fire damper and the adjacent duct structure forming the side walls of outlet chamber 16. Therefore, when the fusible link 36 melts due to dangerous heating, approximately 350 F., the fire damper 35 will automatically close into contact with fixed stops 39 and shut off all draft through the unit to aid in quickly suppressing any fire. A suitable heat sensing probe 40 is mounted to project into the outlet chamber 16 to monitor the temperature in this region in conjunction with certain conventional electrical controls of the fluid fire extinguishing and flushing system, presently tobe described.

As stated, the unit 10 has a built-in liquid spraying system for flushing the interior surfaces of the unit to remove grease deposits and to extinguish any flames that might possibly break out in the unit. This liquid spraying system includes a horizontal inlet pipe 41 for water or water and detergent at the top of the chamber and projecting through one side wall thereof, FIGS. 3 and 5, above the entrance chamber 12. The inlet pipe 41 is connected with a vertical distribution pipe 42 located at the center of the back wall 43 of the unit 10 and extending downwardly for connection at 44 with a horizontal spray header 45 located in the passageway between the chambers 12 and 15 and near the back wall 43. The header 45 has a number of equally spaced forwardly projecting spray nozzles 46 connected therein. As shown in FIGS. 3 and 6, the header 45 spans substantially the entire width of the wide inlet chamber 12 near the top wall thereof. A drain tube 47 connects one end of the header 45 with one of the main drains 29 at one end of chamber 12.

Another horizontal longitudinal header 48 is connected at 49 to the distribution pipe 42, at right angles to the header 45 and well above the same, substantially at the vertical and transverse center of mixing chamber 15. This header 48 extends throughout the length of chamber 15 and is equipped on opposite sides with spaced pairs of liquid spray nozzles 50 for fire extinguishing and for cleaning purposes. An additional spray nozzle 51 is provided on the forward end of the header 48 near the bottom of the outlet chamber 16 just beyond the final vertical baffle 30, FlG. l. The pairs of nozzles 50, as shown in FIGS. 1 and 3 are arranged to effectively spray all surfaces of the baffle plates 22, 24, 26 and 30 as well as all side walls of the chamber 15, and it is in this chamber where most of the grease and oil is removed from the flowing air stream and deposited on the surfaces of the chamber during the normal operation of the extractor.

When the extractor unit l0 is shut down periodically for thorough cleaning with the cooking apparatus turned off and the exhaust fan idle, hot water and detergent under pressure is supplied to the inlet pipe 41 so that all walls of the unit 10 may be thoroughly cleansed of grease. The flushing liquid will drain through the openings 28 into the bottom of chamber 12 and finally will drain out of the unit through the drains 29.

In the event of fire sensed by the probe 40, certain electrical controls, not shown, will activate the liquid spraying system through solenoid valve means, not

shown,'to quickly suppress and extinguish the flame. This will be in conjunction with the closing of the fire damper 35, as described. Additionally the depressed entrance chamber 12 functions to suppress and extinguish any flame near the bottom of the chamber 12 which might be drawn into the slot 18 with the cooking fumes immediately above the cooking apparatus.

It may now be seen that the grease extractor unit 10 is bodily mountable on any wall surface in a very secure and simple manner through the coacting suspension bracket plates 13 and 14. The unit includes a unique depending inlet chamber 12 which is very wide for the initial entering of the air stream through the wide slot 18 and into contact with the inclined baffle plate 20, as described, for creating initial turbulence and swirling and for fire suppressing. From the top of the wide chamber 12, the air stream enters the long horizontal internally baffled mixing chamber 15 through a constricted passage which increases the velocity of the stream and reduces its pressure causing gradual expansion toward the outlet chamber 16. This construction, coupled with the described action of the baffle plates 22, 24, 26 and 30 and their curved extensions, results in the extraction of the maximum amount of contaminants from the air stream and therefore the maximum purifying of the air ultimately exhausted to atmosphere through the duct 17. Most of the contaminants are deposited on the large wall and baffle plate surfaces of chamber 15 where they can be efficiently flushed away by the described action of the built-in spray system. p

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferredexample of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

I claim:

1. A kitchen grease extractor unit comprising a dependent horizontally elongated rectangular cross section inlet chamber adapted for mounting on a vertical wall above a cooking appliance, said inlet chamber having a horizontally elongated inlet slot near its top and on its forward side wall to admit a contaminated air stream into said unit, a baffle at the top of said slot and being coextensive lengthwise therewith and being inclined downwardly and rearwardly from the top of said slot so as to be disposed bodily within the upper portion of the inlet chamber in opposing relation to the incoming air stream, whereby the latter is forced downwardly by said baffle toward the bottom portion of the inlet chamber, a relatively narrow mixing chamber mounted above the inlet chamber and being rectangular in cross section and being horizontally elongated in the frontto-back direction substantially at right angles to the inlet chamber and projecting forwardly of the inlet chamber and communicating with the top of the inlet chamber through a restricted passage which opens into the bottom of the mixing chamber at the rear wall thereof, the inlet chamber disposed bodily below the mixing chamber and extending for substantial equal distances on opposite sides of the mixing chamber, plural spaced alternately upstanding and depending baffle plates mounted in the mixing chamber and extending across the entire width thereof, the interior ends of said baffle plates being curled and lying substantially at the vertical center of the mixing chamber to form a zigzag up-and-down passage for the air stream flowing therethrough, one baffle plate rising directly above the forward side wall of the inlet chamber and above the forward edge of said restricted passage, a liquid spraying posed at the rear side wall of said outlet chamber.

2. The structure of claim 1, and a fusible link damper disposed within said rising outlet chimney chamber.

3. The structure of claim 1, and support bracket header within the mixing chamber lengthwise thereof means on said grease extractor unit for attaching it to at approximately the vertical and horizontal centers of the mixing chamber and having plural divergent nozzle means thereon, and a rising outlet chimney chamber on the forward end of said mixing chamber and being of substantially the same width as the mixing chamber and adapted for connection with a rising exhaust duct, one of said baffle plates in the mixing chamber being disthe inlet and mixing chambers. 

1. A kitchen grease extractor unit comprising a dependent horizontally elongated rectangular cross section inlet chamber adapted for mounting on a vertical wall above a cooking appliance, said inlet chamber having a horizontally elongated inlet slot near its top and on its forward side wall to admit a contaminated air stream into said unit, a baffle at the top of said slot and being coextensive lengthwise therewith and being inclined downwardly and rearwardly from the top of said slot so as to be disposed bodily within the upper portion of the inlet chamber in opposing relation to the incoming air stream, whereby the latter is forced downwardly by said baffle toward the bottom portion of the inlet chamber, a relatively narrow mixing chamber mounted above the inlet chamber and being rectangular in cross section and being horizontally elongated in the front-to-back direction substantially at right angles to the inlet chamber and projecting forwardly of the inlet chamber and communicating with the top of the inlet chamber through a restricted passage which opens into the bottom of the mixing chamber at the rear wall thereof, the inlet chamber disposed bodily below the mixing chamber and extending for substantial equal distances on opposite sides of the mixing chamber, plural spaced alternately upstanding and depending baffle plates mounted in the mixing chamber and extending across the entire width thereof, the interior ends of said baffle plates being curled and lying substantially at the vertical center of the mixing chamber to form a zigzag up-anddown passage for the air stream flowing therethrough, one baffle plate rising directly above the forward side wall of the inlet chamber and above the forward edge of said restricted passage, a liquid spraying header within the mixing chamber lengthwise thereof at approximately the vertical and horizontal centers of the mixing chamber and having plural divergent nozzle means thereon, and a rising outlet chimney chamber on the forward end of said mixing chamber and being of substantially the same width as the mixing chamber and adapted for connection with a rising exhaust duct, one of said baffle plates in the mixing chamber being disposed at the rear side wall of said outlet chamber.
 2. The structure of claim 1, and a fusible link damper disposed within said rising outlet chimney chamber.
 3. The structure of claim 1, and support bracket means on said grease extractor unit for attaching it to a vertical wall.
 4. The structure of claim 1, and said liquid spraying header including a horizontal extension adjacent the top of said inlet chamber and adjacent the rear walls of the inlet and mixing chambers. 